Code:
Z:\Media\CalibreLibrary\CALIBRE_CONFIG_DIRECTORY
Does this path actually exist? Including the exact same case?
IIRC Calibre (at run time)will not create the whole path, only the containing older
ALSO it needs FULL rights to
\Media
Z:\Media\
CalibreLibrary <this is not the Library folder?? AFAIK nothing else can be inside
Z:\Media\CALIBRE_CONFIG_DIRECTORY would be OK, it is alongside